All About Ferrites

7/26/2021

In this show George, Mark, Rod and Mike talk about what's on their workbenches and take a deep dive into the topic of ferrites. We explore what they are, how they work and practical applications.

SHOW NOTES

QSO Today Expo https://www.qsotodayhamexpo.com/

Jetstream JTBM270 3-ELEMENT 2M 5-ELEM 70CM DUAL BAND VHF UHF YAGI BEAM ANTENNA
https://www.ebay.com/itm/401688089979?epid=1124956691&hash=item5d8679d57b:g:gJ0AAOSwHPlWfa1F

Rig Expert AA-650 Antenna Analyzer
https://www.dxengineering.com/parts/reu-aa-650zoom

Stream Deck - Large version
https://www.amazon.com/Elgato-Stream-Deck-XL-customizable/dp/B07RL8H55Z/ref=sr_1_3?dchild=1&keywords=stream+deck&qid=1627088153&sr=8-3

Toroids.info

Resources
The ARRL Handbook, specifically
Volume 2 chapter 5, section 5.5 of the 2020 handbook
“Ferrite Materials” (5 pages of rich goodness)
And
Volume 5 Chapter 22 - (ferrite component sizes, values in tables)

Where should I buy them ?
Digikey
Palomar Engineers
Amidon Associates

3 Comments

jim Sutton link

7/28/2021 10:25:07

Mike and Georges comment's about VHF/UHF radios sent me on a search for a D710 or FTM-7250 which resulted in a show idea. Buying and selling online - where to look, what to look for or look out for. How to write a great ad if you are trying to sell something.
Keep up the great work - 73

John VE3IPS

8/17/2021 09:49:53

How to identify junkbox cores ferrite materials :-)

G8JNJ: Baluns and Tuners:
http://www.g8jnj.net/Balun%20construction.pdf
http://web.archive.org/web/20170806130801/http://www.g8jnj.net/Balun%20construction.pdf
Citat: "...
The easiest way to identify most ferrite materials is to wind about four turns of wire through the core and then measure the lowest frequency at which the value of reactive impedance equal resistive impedance i.e. X=R. There will be some variation between different batches and sizes of materials. But if you can plot the results graphically you can easily identify the 'signature' of each material.
Here are my references for some common ferrite materials
FT240-77 0.74MHz
FT240-31 3.5MHz
FT100-33 7MHz
FT240-43 17MHz
FT240-K 22MHz
FT240-52 31MHz
FT240-61 58MHz
Iron powder has a slightly different 'signature' it usually has a very low resistive component, which peaks to a higher value near self resonance. The more lossy the material the broader and lower value of resistive peak is apparent.
T200-52 40MHz Lime Green (& Blue or Red) colour common in PC switch mode power supplies - moderate loss
T200-26 60MHz Yellow & White colour common in PC switch mode power supplies - high loss
T200-2 60MHz Dark Red colour used for HF tuned circuits (& Ruthoff Ununs) - high Q low loss
T200-1 70MHz Blue colour not common - moderate loss
T200-6 100MHz Yellow colour used for VHF tuned circuits - high Q low loss

Sonny

9/29/2021 18:04:59

Im 1/2 way through it and nothing about Ferrites yet. Come on!

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All About Ferrites

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